Prokaryotic cell reproductionBinary Fission

Eukaryotic Cell Cycle

Eukaryotic Cell Reproduction: Mitosis & Meiosis

Mitosis: cell reproduction for growth and replacement of cells. This makes identical copies (clones)

Meiosis: cell reproduction for the production of gametes, such as egg and sperm (sex cells)

How many chromosomes in a human cell such as a skin cell?

How many chromosomes in egg and sperm?

Human Karyotype

Is this person male or female?

46

46 46

MitosisOne division

46

46 46

chromosomes

replication

chromatids chromatids

chromosomes

chromosomes chromosomes 23 23 23 23

chromosomesMeiosisTwo divisions

Mitosis: cell reproduction for growth and replacement of cells. This makes identical copies (clones)

What are some examples of mitosis in the body?• Cuts and scrapes• Embryonic growth• Aging• Stomach cells

What are some examples of mitosis in other organisms?• Asexual reproduction (budding and fragmentation)• Plants: growth of roots and stems• Regeneration (starfish arm, lizard tail)

46

46 46

MitosisOne division

46

46 46

chromosomes

replication

chromatids chromatids

chromosomes

chromosomes chromosomes 23 23 23 23

chromosomesMeiosisTwo divisions

Sister Chromatids

Chromosome Sister Chromatids

DNA Replication

centromere

Phases in Mitosis

• Interphase: DNA replication• Prophase: chromosomes thicken, nucleus

disappears• Metaphase: chromosomes line up at

center• Anaphase: centromeres split, sister

chromatids separate• Telophase: cytokinesis, division of the

cytoplasm

Applications of Mitosis?

Cancer = abnormalgrowth of cells

Control of the Cell Cycle

MPFis a proteinthat triggersmitosis.

Where is MPFin high amountsand in lowamounts?

Regulation of Cell Cycle

• What controls cell reproduction?• MPF = Maturation Promoting Factor

MPF = cyclin + cdk (cdc2)Protein Kinase = activates other proteinsi.e. spindle fibers that move chromosomes

• Two functions of MPF:1. triggers mitosis2. activates enzymes to breakdown cyclin (negative feedback)

Cancer

• Transformation = process that converts a normal cell to a cancer cell

• Tumor = loss of cell cycle control = abnormal growth of cells

• Benign = noncancerous, Malignant = cancerous

• Metastasis = spread rate of a malignant cancer to locations other than their origin

(tumor cells enter blood vessels and travel to other parts of the body)

Meiosis: cell reproduction for the production of gametes, such as egg and sperm (sex cells)

•Meiosis cuts the number of chromosomes in half

•Meiosis occurs in gonads

•Gonads are reproductive organs (such as ovaries and testes)

•2 divisions1st Meiotic division 2nd Meiotic divisionInterphase Prophase IIProphase I Metaphase IIMetaphase I Anaphase IIAnaphase I Telophase IITelophase I

Homologous Pair (Homologous Chromosomes)

• Chromosomes that carry genes in the same place for the same traits

• One is maternal in origin (from the egg)

• The other is paternal in origin (from the sperm)

Hair colorEye colorSkin tone

hitchikersearlobeswidow’s

1st Meiotic Division

• Interphase: DNA replication

• Prophase I: crossing over

• Metaphase I: independent assortment

• Anaphase I: homologous pairs separate, centromeres intact

• Telophase I: cytokinesis

2nd Meiotic Division

• Prophase II: reorganization, no crossing over

• Metaphase II: chromosomes line up with centromere on line

• Anaphase II: centromere splits, sister chromatids separate

• Telophase II: cytokinesis